Microsoft integrates Skype and Outlook with Skype 6.1

Users can now send an instant message or make a Skype call direct from Outlook

From V3:

Users can message any of their Skype contacts directly from Outlook, while Skype can also be used to initiate a voice call to mobile and landline numbers as well as direct Skype-to-Skype calls.

Microsoft said that the integration allows users to call anyone whose contact information is in Outlook, even if that person is not a Skype contact. However, calls other than Skype-to-Skype sessions require Skype credit or a subscription, as usual.